The presence of methyl tert-butyl ether (MTBE), a component used to add oxygen to gasoline to meet Clean Air Act standards, has been detected as a contaminant in ground water supplies underlying urban areas, particularly in the northeastern United States. The study is published in the July-August issue of Ground Water.

Researchers from the U.S. Geological Survey examined the occurrence of MTBE and gasoline hydrocarbons in ground water throughout the United States and found that nationwide, MTBE was detected as frequently as some other chemicals that have been used for longer periods of time. MTBE was detected more frequently in urban areas compared to other land use types, such as agricultural areas, putting shallow ground water supply in these areas at risk for contamination.

"It is not known if contamination of shallow ground water in urban areas will reach deeper aquifers that are generally used for supplying drinking water," states Michael J. Moran, lead researcher. "Few concentrations of MTBE in ground water exceed the current U.S. EPA Drinking-Water Advisory. This means that most MTBE concentrations in ground water will not cause taste and odor concerns. However, low concentrations of MTBE in drinking water may have unforeseen health consequences."

Past research has shown that possible human health consequences as a result of MTBE contamination in drinking water include carcinogenesis and detrimental reproductive and developmental effects. Researchers say determining the factors related to the occurrence of MTBE, as in this study, may help to reveal the sources and pathways of MTBE to ground water, and the vulnerability of aquifers to MTBE contamination.